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Outboard Boat Engine Components

Selecting the right type of engine for your vessel can mean a smoother ride and more enjoyable outboard boating experience. Choosing the proper components for your engine can ensure a lifetime of fun on the water. When you need to replace engine components, it is helpful to know what parts you need and how they work.

What is an outboard engine?

This type of engine is part of an outboard motor that is a boat propulsion system designed to attach to the stern. The engine is a self-contained internal combustion unit that can be added and removed as required. Outboard motors are the most common way to propel small watercraft. Their compact size and easy removal make repairs and replacements simple to accomplish. Evinrude, Yamaha, Mercury, Suzuki Marine, and Honda make a variety of outboard engines for the boating industry.

How does an outboard engine run?

Fuel (usually gasoline) is combusted in the outboard gas tank cylinders that then move the pistons back and forth in a four-stroke cycle just like your car engine (some simpler outboard motors, though, use a two-stroke cycle). The pistons then turn the crankshaft, and the direction of the motion changes to round and round. The crankshaft then moves the main driveshaft. The components, which are then spinning vertically, are converted to horizontal motion by a gearbox at the end of the driveshaft. The horizontally spinning gears power the propeller that moves the boat over the water.

What components does an outboard boat motor have?

While outboard motors can come in a variety of configurations due to size, strength, and manufacturer, most of them come with some basic components:

  • Cylinder: This is where the fuel burns. The engines can have from two to eight cylinders.
  • Pistons: Pistons move back and forth to drive the crankshaft.
  • Carburetor: The carburetor is where the fuel meets air to create the explosive energy that gets the pistons moving.
  • Fuel pump: This component moves fuel to the carburetor.
  • Spark plugs: Spark plugs serve to ignite the fuel.
  • Camshaft: This component opens and closes the valves to move fuel in and exhaust out.
  • Driveshaft: This component transfers power from the crankshaft to the gears.
  • Propellers: The propeller displaces the water to move the boat. Also called a prop, this component is usually made of aluminum or stainless steel and normally has three to four blades. Some high-power boats may have five to six blades.
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